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Gros M, Gros B, Mesonero JE, Latorre E. Neurotransmitter Dysfunction in Irritable Bowel Syndrome: Emerging Approaches for Management. J Clin Med 2021; 10:jcm10153429. [PMID: 34362210 PMCID: PMC8347293 DOI: 10.3390/jcm10153429] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/13/2021] [Accepted: 07/28/2021] [Indexed: 02/06/2023] Open
Abstract
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder whose aetiology is still unknown. Most hypotheses point out the gut-brain axis as a key factor for IBS. The axis is composed of different anatomic and functional structures intercommunicated through neurotransmitters. However, the implications of key neurotransmitters such as norepinephrine, serotonin, glutamate, GABA or acetylcholine in IBS are poorly studied. The aim of this review is to evaluate the current evidence about neurotransmitter dysfunction in IBS and explore the potential therapeutic approaches. IBS patients with altered colorectal motility show augmented norepinephrine and acetylcholine levels in plasma and an increased sensitivity of central serotonin receptors. A decrease of colonic mucosal serotonin transporter and a downregulation of α2 adrenoceptors are also correlated with visceral hypersensitivity and an increase of 5-hydroxyindole acetic acid levels, enhanced expression of high affinity choline transporter and lower levels of GABA. Given these neurotransmitter dysfunctions, novel pharmacological approaches such as 5-HT3 receptor antagonists and 5-HT4 receptor agonists are being explored for IBS management, for their antiemetic and prokinetic effects. GABA-analogous medications are being considered to reduce visceral pain. Moreover, agonists and antagonists of muscarinic receptors are under clinical trials. Targeting neurotransmitter dysfunction could provide promising new approaches for IBS management.
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Affiliation(s)
- Mónica Gros
- Centro de Salud Univérsitas, Hospital Clínico Universitario Lozano Blesa, 50009 Zaragoza, Spain;
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), 50009 Zaragoza, Spain; (B.G.); (J.E.M.)
| | - Belén Gros
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), 50009 Zaragoza, Spain; (B.G.); (J.E.M.)
- Servicio de Urgencias, Hospital Universitario Miguel Servet, 50009 Zaragoza, Spain
| | - José Emilio Mesonero
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), 50009 Zaragoza, Spain; (B.G.); (J.E.M.)
- Departamento de Farmacología, Fisiología y Medicina Legal y Forense, Facultad de Veterinaria, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Instituto Agroalimentario de Aragón—IA2—(Universidad de Zaragoza—CITA), 50013 Zaragoza, Spain
| | - Eva Latorre
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), 50009 Zaragoza, Spain; (B.G.); (J.E.M.)
- Instituto Agroalimentario de Aragón—IA2—(Universidad de Zaragoza—CITA), 50013 Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Correspondence:
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Glutamatergic Signaling Along The Microbiota-Gut-Brain Axis. Int J Mol Sci 2019; 20:ijms20061482. [PMID: 30934533 PMCID: PMC6471396 DOI: 10.3390/ijms20061482] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/04/2019] [Accepted: 03/21/2019] [Indexed: 12/21/2022] Open
Abstract
A complex bidirectional communication system exists between the gastrointestinal tract and the brain. Initially termed the “gut-brain axis” it is now renamed the “microbiota-gut-brain axis” considering the pivotal role of gut microbiota in maintaining local and systemic homeostasis. Different cellular and molecular pathways act along this axis and strong attention is paid to neuroactive molecules (neurotransmitters, i.e., noradrenaline, dopamine, serotonin, gamma aminobutyric acid and glutamate and metabolites, i.e., tryptophan metabolites), sustaining a possible interkingdom communication system between eukaryota and prokaryota. This review provides a description of the most up-to-date evidence on glutamate as a neurotransmitter/neuromodulator in this bidirectional communication axis. Modulation of glutamatergic receptor activity along the microbiota-gut-brain axis may influence gut (i.e., taste, visceral sensitivity and motility) and brain functions (stress response, mood and behavior) and alterations of glutamatergic transmission may participate to the pathogenesis of local and brain disorders. In this latter context, we will focus on two major gut disorders, such as irritable bowel syndrome and inflammatory bowel disease, both characterized by psychiatric co-morbidity. Research in this area opens the possibility to target glutamatergic neurotransmission, either pharmacologically or by the use of probiotics producing neuroactive molecules, as a therapeutic approach for the treatment of gastrointestinal and related psychiatric disorders.
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Volpi C, Fallarino F, Mondanelli G, Macchiarulo A, Grohmann U. Opportunities and challenges in drug discovery targeting metabotropic glutamate receptor 4. Expert Opin Drug Discov 2018; 13:411-423. [DOI: 10.1080/17460441.2018.1443076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Claudia Volpi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | | | - Giada Mondanelli
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Antonio Macchiarulo
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Ursula Grohmann
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
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Filpa V, Moro E, Protasoni M, Crema F, Frigo G, Giaroni C. Role of glutamatergic neurotransmission in the enteric nervous system and brain-gut axis in health and disease. Neuropharmacology 2016; 111:14-33. [PMID: 27561972 DOI: 10.1016/j.neuropharm.2016.08.024] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/18/2016] [Accepted: 08/18/2016] [Indexed: 02/07/2023]
Abstract
Several studies have been carried out in the last 30 years in the attempt to clarify the possible role of glutamate as a neurotransmitter/neuromodulator in the gastrointestinal tract. Such effort has provided immunohistochemical, biomolecular and functional data suggesting that the entire glutamatergic neurotransmitter machinery is present in the complex circuitries of the enteric nervous system (ENS), which participates to the local coordination of gastrointestinal functions. Glutamate is also involved in the regulation of the brain-gut axis, a bi-directional connection pathway between the central nervous system (CNS) and the gut. The neurotransmitter contributes to convey information, via afferent fibers, from the gut to the brain, and to send appropriate signals, via efferent fibers, from the brain to control gut secretion and motility. In analogy with the CNS, an increasing number of studies suggest that dysregulation of the enteric glutamatergic neurotransmitter machinery may lead to gastrointestinal dysfunctions. On the whole, this research field has opened the possibility to find new potential targets for development of drugs for the treatment of gastrointestinal diseases. The present review analyzes the more recent literature on enteric glutamatergic neurotransmission both in physiological and pathological conditions, such as gastroesophageal reflux, gastric acid hypersecretory diseases, inflammatory bowel disease, irritable bowel syndrome and intestinal ischemia/reperfusion injury.
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Affiliation(s)
- Viviana Filpa
- Department of Clinical and Experimental Medicine, University of Insubria, via H. Dunant 5, I-21100 Varese, Italy
| | - Elisabetta Moro
- Department of Internal Medicine and Therapeutics, Section of Pharmacology, via Ferrata 9, I-27100 Pavia, Italy
| | - Marina Protasoni
- Department of Surgical and Morphological Sciences, University of Insubria, via F. Guicciardini 9, I-21100 Varese, Italy
| | - Francesca Crema
- Department of Internal Medicine and Therapeutics, Section of Pharmacology, via Ferrata 9, I-27100 Pavia, Italy
| | - Gianmario Frigo
- Department of Internal Medicine and Therapeutics, Section of Pharmacology, via Ferrata 9, I-27100 Pavia, Italy
| | - Cristina Giaroni
- Department of Clinical and Experimental Medicine, University of Insubria, via H. Dunant 5, I-21100 Varese, Italy
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Goto TK, Yeung AWK, Tanabe HC, Ito Y, Jung HS, Ninomiya Y. Enhancement of Combined Umami and Salty Taste by Glutathione in the Human Tongue and Brain. Chem Senses 2016; 41:623-30. [PMID: 27353260 DOI: 10.1093/chemse/bjw066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glutathione, a natural substance, acts on calcium receptors on the tongue and is known to enhance basic taste sensations. However, the effects of glutathione on brain activity associated with taste sensation on the tongue have not been determined under standardized taste delivery conditions. In this study, we investigated the sensory effect of glutathione on taste with no effect of the smell when glutathione added to a combined umami and salty taste stimulus. Twenty-six volunteers (12 women and 14 men; age 19-27 years) performed a sensory evaluation of taste of a solution of monosodium L-glutamate and sodium chloride, with and without glutathione. The addition of glutathione changed taste qualities and significantly increased taste intensity ratings under standardized taste delivery conditions (P < 0.001). Functional magnetic resonance imaging showed that glutathione itself elicited significant activation in the left ventral insula. These results are the first to demonstrate the enhancing effect of glutathione as reflected by brain data while tasting an umami and salty mixture.
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Affiliation(s)
- Tazuko K Goto
- Oral Diagnosis & Polyclinics, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Hong Kong, Department of Oral and Maxillofacial Radiology, Tokyo Dental College, 2-9-18, Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan,
| | - Andy Wai Kan Yeung
- Oral Diagnosis & Polyclinics, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Hong Kong
| | - Hiroki C Tanabe
- Graduate School of Environmental Studies, Department of Social and Human Environment, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Yuki Ito
- Mitsubishi Shoji Foodtech Co., Ltd., 1-1-3, Yurakucho, Chiyoda-ku, Tokyo 100-0006, Japan, Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Han-Sung Jung
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Hong Kong
| | - Yuzo Ninomiya
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan, Division of Sensory Physiology, Research and Development Center for Taste and Odor Sensing, Kyushu University, Collaboration station II, 307/308, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan and Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA19104-3308, USA
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Grados M, Prazak M, Saif A, Halls A. A review of animal models of obsessive-compulsive disorder: a focus on developmental, immune, endocrine and behavioral models. Expert Opin Drug Discov 2015; 11:27-43. [PMID: 26558411 DOI: 10.1517/17460441.2016.1103225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by intrusive thoughts (obsessions) and/or repetitive behaviors (compulsions). Several models of OCD exist, many which employ behaviors such as over-grooming or hoarding as correlates for compulsive behaviors - often using a response to serotonergic agents as evidence for their validity. Recent discoveries in the genetics of OCD and the identification of aberrancies of glutamatergic, hormonal, and immune pathways in the OCD phenotype highlight a need to review existing of animal models of OCD. The focus of attention to these pathways may lead to possible new targets for drug discovery. AREAS COVERED In this review, the authors describe frameworks for animal models in OCD conceptualized as either biological (e.g., developmental, genetic, and endocrine pathways), or behavioral (e.g., repetitive grooming, and stereotypies). In addition, the authors give special attention to the emerging role of glutamate in OCD. EXPERT OPINION While many animal models for OCD demonstrate pathologic repetitive behavior phenotypes, which are relieved by serotoninergic agents, animal models based on reversal learning, perseverative responding, and neurodevelopmental mechanisms represent robust new paradigms. Glutamatergic influences in these new animal models suggest that drug discovery using neuroprotective approaches may represent a new stage for pharmacologic developments in OCD.
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Affiliation(s)
- Marco Grados
- a Department of Psychiatry , Johns Hopkins University , 1800 Orleans St. - 12th floor, Baltimore , MD 21287 , USA
| | - Michael Prazak
- b Department of Medicine , Dow University of Health Sciences , Karachi , Pakistan
| | - Aneeqa Saif
- c Department of Psychology Grand Forks , University of North Dakota , ND , USA
| | - Andrew Halls
- a Department of Psychiatry , Johns Hopkins University , 1800 Orleans St. - 12th floor, Baltimore , MD 21287 , USA
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